The present invention relates to optical coders for locating by dioscopy the position of a mobile element.
It is known that such a coder comprises a disk or strip comprising several tracks, each with a succession of alternating opaque zones and transparent zones, and a reading assembly comprising a light source and one or more photodetectors which detect for each track whether an opaque zone or a transparent zone is present in front of the photodetectors(s); the disk or strip and the reading assembly are mobile with respect to each other either in rotation for, or in translation (for the strip). In addition, an electronic unit may be associated with the photodetector(s) for processing the signals emitted by the photodetector(s).
Generally, the assembly of this system is small, and when the components are distant from each other, conductors provide the electrical connections, for example, between the power supply means, the optoelectronic system forming the reading assembly and the electronic signal processing unit.
In some applications there exists a large distance between the reading assembly and the electronic signal processing unit. Any electric connection between these two units should be avoided because such a connection would risk being disturbed by outside interferences, particularly in the case of analog transmission of the signals between the reading unit and the electric signal processing unit.